Because you included the word 'you'.
Any title with the words you, your, best, favorite/favourite, worst, and hardest get this warning. It's kind of outdated; see What algorithm does Stack Exchange use to determine if a question may be subjective? on Meta.SE.
I think this is relatively simple.
If the question is "here's my theory; is there evidence within the canon material to support it?", I think it is okay.
If instead the question is "here's my theory; what do you think?", it needs to be fixed.
While I agree that a good version of a "pet theory" question should provide examples ...
Despite the comment I left, I actually thought your question was ok and had some grounds under good subjective, but it's definitely subjective. Case in point: I wouldn't find any episodes in TNG worth skipping, despite their reception. Perhaps you need to tackle this with a slightly different approach.
The criteria of the episodes you don't want to miss is ...